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Snakebite envenomation is a serious health concern in tropical regions, resulting in high mortality. The World Health Organization (WHO) has declared it a neglected tropical disease and is working on strategies to reduce mortality. Russell's viper (Daboia russelii) is one of the most abundant venomous snakes found across Southeast Asia. Proteomic analysis of Russell's viper venom has demonstrated variation, with phospholipase A2 (PLA2) being the most abundant toxin across geographic boundaries. PLA2, a major constituent of the low-molecular-weight fraction of snake venom, hydrolyses phospholipids at the sn-2 position, releasing arachidonic acid and lysophospholipids. They are reported to cause various pharmacological effects, including hemolysis, anticoagulation, neurotoxicity, myotoxicity, and oedema. Though administration of antivenoms (ASV) is the primary treatment for envenomation, it has many drawbacks. Besides causing hypersensitivity reactions and life-threatening anaphylaxis, treatment with ASV is further complicated due to its inability to neutralize low-molecular-weight toxins. Thus, there is a greater need to produce next-generation antivenoms that can target specific toxins in the venom. In this review, we explored the classification of Russell's viper and the variation in its proteomic profile across Southeast Asia to date. In addition, we have also summarized the mechanism of action of PLA2 and discussed various isoforms of PLA2 found across different regions with their respective pharmacological effects. Finally, the drawbacks of commercially available antivenoms and the molecules investigated for inhibiting the low-molecular-weight toxin, PLA2 are discussed. [ABSTRACT FROM AUTHOR]

Life-threatening medical issues can result from snakebite, and hence this is a public health concern. In many tropical and subtropical nations such as Kenya, where a wide variety of poisonous snakes are prevalent, diagnosis of snakebite in health facilities is imperative. Different antivenoms are needed to treat the venom of different snake species. Nonetheless, it might be difficult for medical professionals to identify the exact snake species that envenomated a patient due to the similarities of several snake envenomations' clinical symptoms. Therefore, the necessity for an assay or technique for identifying venomous species is critical. The current study sought to develop a sensitive ELISA prototype for the detection of D. polylepis venom in Kenya using generated chicken-based IgY polyclonal antibodies. Serum samples containing specific chicken-based IgY antibodies previously raised against D. polylepis venom toxins were used in the assay development. ELISA parameters were optimized, and the developed assay was assessed for applicability. The limit of detection (LoD) of the ELISA for neurotoxic venoms was determined to be 0.01 µg/mL. Successful discrimination between neurotoxic and cytotoxic venoms was achieved by the ensuing inhibition ELISA assay. The developed assay showed the capability of identifying venoms in blood samples (from spiked and venom-challenged blood samples) of BALB/c mice, providing compelling evidence of the strategy's usefulness. This assay could help physicians diagnose and manage victims of snakebites through the evaluation of clinical samples. [ABSTRACT FROM AUTHOR]

Five peptides were isolated from the venom of the Mexican scorpion Centruroides bonito by chromatographic procedures (molecular weight sieving, ion exchange columns, and HPLC) and were denoted Cbo1 to Cbo5. The first four peptides contain 66 amino acid residues and the last one contains 65 amino acids, stabilized by four disulfide bonds, with a molecular weight spanning from about 7.5 to 7.8 kDa. Four of them are toxic to mice, and their function on human Na+ channels expressed in HEK and CHO cells was verified. One of them (Cbo5) did not show any physiological effects. The ones toxic to mice showed that they are modifiers of the gating mechanism of the channels and belong to the beta type scorpion toxin (β-ScTx), affecting mainly the Nav1.6 channels. A phylogenetic tree analysis of their sequences confirmed the high degree of amino acid similarities with other known bona fide β-ScTx. The envenomation caused by this venom in mice is treated by using commercially horse antivenom available in Mexico. The potential neutralization of the toxic components was evaluated by means of surface plasmon resonance using four antibody fragments (10FG2, HV, LR, and 11F) which have been developed by our group. These antitoxins are antibody fragments of single-chain antibody type, expressed in E. coli and capable of recognizing Cbo1 to Cbo4 toxins to various degrees. [ABSTRACT FROM AUTHOR]

Snakebite accident treatment requires the administration of antivenoms that provide efficacy and effectiveness against several snake venoms of the same genus or family. The low number of immunogenic components in venom mixtures that allow the production of antivenoms consequently gives them partial neutralization and a suboptimal pharmacological response. This study evaluates the immunorecognition and neutralizing efficacy of the polyvalent anticoral antivenom from the Instituto Nacional de Salud (INS) of Colombia against the heterologous endemic venoms of Micrurus medemi, and M. sangilensis, and M. helleri by assessing immunoreactivity through affinity chromatography, ELISA, Western blot, and neutralization capability. Immunorecognition towards the venoms of M. medemi and M. sangilensis showed values of 62% and 68% of the protein composition according to the immunoaffinity matrix, respectively. The analysis by Western blot depicted the highest recognition patterns for M. medemi, followed by M. sangilensis, and finally by M. helleri. These findings suggest that the venom compositions are closely related and exhibit similar recognition by the antivenom. According to enzyme immunoassays, M. helleri requires a higher amount of antivenom to achieve recognition than the others. Besides reinforcing the evaluation of INS antivenom capability, this work recommends the use of M. helleri in the production of Colombian antisera. [ABSTRACT FROM AUTHOR]

Crotalus culminatus is a medically significant species of rattlesnake in Mexico [1]. While the proteomic composition of its venom has been previously reported for both juvenile and adult specimens, there has been limited research into its functional properties, with only a few studies, including one focusing on coagulotoxicity mechanisms. In this study, we aimed to compare the biochemical and biological activities of the venom of juvenile and adult snakes. Additionally, we assessed antibody production using the venoms of juveniles and adults as immunogens in rabbits. Our findings reveal lethality and proteolytic activity differences between the venoms of juveniles and adults. Notably, juvenile venoms exhibited high proportions of crotamine, while adult venoms displayed a reduction of this component. A commercially available antivenom demonstrated effective neutralization of lethality of both juvenile and adult venoms in mice. However, it failed to neutralize the paralytic activity induced by crotamine, which, in contrast, was successfully inhibited by antibodies obtained from hyperimmunized rabbits. These results suggest the potential inclusion of C. culminatus venom from juveniles in commercial antivenom immunization schemes to generate antibodies targeting this small myotoxin. [Display omitted] • Crotalus culminatus venoms were comparatively analyzed. • Juvenile venom had higher crotamine levels than adult venom. • Commercial antivenom effectively neutralized the lethality of both adult and juvenile venoms. • Antivenom did not neutralize crotamine, as rigid paralysis in mice remained evident. • Rabbits immunized with adult or juvenile venoms produced neutralizing antibodies against the lethal activity of the venoms. [ABSTRACT FROM AUTHOR]

The many-banded krait, Bungarus multicinctus, has been recorded as the animal resource of JinQianBaiHuaShe in the Chinese Pharmacopoeia. Characterization of its venoms classified chief phyla of modern animal neurotoxins. However, the evolutionary origin and diversification of its neurotoxins as well as biosynthesis of its active compounds remain largely unknown due to the lack of its high-quality genome. Here, we present the 1.58 Gbp genome of B. multicinctus assembled into 18 chromosomes with contig/scaffold N50 of 7.53 Mbp/149.8 Mbp. Major bungarotoxin-coding genes were clustered within genome by family and found to be associated with ancient local duplications. The truncation of glycosylphosphatidylinositol anchor in the 3′-terminal of a LY6E paralog released modern three-finger toxins (3FTxs) from membrane tethering before the Colubroidea divergence. Subsequent expansion and mutations diversified and recruited these 3FTxs. After the cobra/krait divergence, the modern unit-B of β-bungarotoxin emerged with an extra cysteine residue. A subsequent point substitution in unit-A enabled the β-bungarotoxin covalent linkage. The B. multicinctus gene expression, chromatin topological organization, and histone modification characteristics were featured by transcriptome, proteome, chromatin conformation capture sequencing, and ChIP-seq. The results highlighted that venom production was under a sophisticated regulation. Our findings provide new insights into snake neurotoxin research, meanwhile will facilitate antivenom development, toxin-driven drug discovery and the quality control of JinQianBaiHuaShe.

Life-threatening medical issues can result from snakebite, and hence this is a public health concern. In many tropical and subtropical nations such as Kenya, where a wide variety of poisonous snakes are prevalent, diagnosis of snakebite in health facilities is imperative. Different antivenoms are needed to treat the venom of different snake species. Nonetheless, it might be difficult for medical professionals to identify the exact snake species that envenomated a patient due to the similarities of several snake envenomations’ clinical symptoms. Therefore, the necessity for an assay or technique for identifying venomous species is critical. The current study sought to develop a sensitive ELISA prototype for the detection of D. polylepis venom in Kenya using generated chicken-based IgY polyclonal antibodies. Serum samples containing specific chicken-based IgY antibodies previously raised against D. polylepis venom toxins were used in the assay development. ELISA parameters were optimized, and the developed assay was assessed for applicability. The limit of detection (LoD) of the ELISA for neurotoxic venoms was determined to be 0.01 µg/mL. Successful discrimination between neurotoxic and cytotoxic venoms was achieved by the ensuing inhibition ELISA assay. The developed assay showed the capability of identifying venoms in blood samples (from spiked and venom-challenged blood samples) of BALB/c mice, providing compelling evidence of the strategy’s usefulness. This assay could help physicians diagnose and manage victims of snakebites through the evaluation of clinical samples.

Snakebite incidence varies across Europe. However, there is limited research from Central and Southeastern Europe. These regions are notable for the presence of the common European adder (Vipera berus) and the more venomous nose-horned viper (Vipera ammodytes). No standard European antivenom protocol exists. The aim was to assess the epidemiology and treatment of viper bites in this region, focusing on a comparison of bites from Vipera berus and Vipera ammodytes. We conducted a prospective multicenter study in Central and Southeastern Europe from 2018 to 2020. This study included poison centres and toxicology-associated hospital wards in Poland, the Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Serbia, and Bulgaria. The following data were collected: age, gender, Vipera species, snakebite site, clinical picture, laboratory results, Audebert's clinical severity grading score, and antivenom therapy. The annual incidence of viper bites in Central and Southeast Europe was estimated at 2.55 bites per million population. Within their respective geographical distribution areas, the incidence of Vipera ammodytes bites (1.61 bites per million population) was higher than Vipera berus bites (1.00 bites per million population). Patients bitten by Vipera ammodytes more frequently reported local pain and developed thrombocytopenia. Antivenom treatment was more commonly administered in Vipera ammodytes bites (72%) compared to Vipera berus bites (39%). The incidence of Vipera ammodytes bites treated with antivenom within its geographical distribution area was three times higher than Vipera berus bites treated with antivenom (1.16 bites per million population versus 0.39 bites per million population). No deaths were reported. The estimated incidence of viper bites in Central and Southeastern Europe is at least 2.55 per million population. Vipera ammodytes bites are more common and severe, characterized by higher frequencies of pain and thrombocytopenia. Antivenom is needed more often for Vipera ammodytes bites. It is vital that enough European Medicines Agency-approved Vipera ammodytes antivenom is produced and offered affordably. [ABSTRACT FROM AUTHOR]

The many-banded krait, Bungarus multicinctus , has been recorded as the animal resource of JinQianBaiHuaShe in the Chinese Pharmacopoeia. Characterization of its venoms classified chief phyla of modern animal neurotoxins. However, the evolutionary origin and diversification of its neurotoxins as well as biosynthesis of its active compounds remain largely unknown due to the lack of its high-quality genome. Here, we present the 1.58 Gbp genome of B. multicinctus assembled into 18 chromosomes with contig/scaffold N50 of 7.53 Mbp/149.8 Mbp. Major bungarotoxin-coding genes were clustered within genome by family and found to be associated with ancient local duplications. The truncation of glycosylphosphatidylinositol anchor in the 3′-terminal of a LY6E paralog released modern three-finger toxins (3FTxs) from membrane tethering before the Colubroidea divergence. Subsequent expansion and mutations diversified and recruited these 3FTxs. After the cobra/krait divergence, the modern unit-B of β -bungarotoxin emerged with an extra cysteine residue. A subsequent point substitution in unit-A enabled the β -bungarotoxin covalent linkage. The B. multicinctus gene expression, chromatin topological organization, and histone modification characteristics were featured by transcriptome, proteome, chromatin conformation capture sequencing, and ChIP-seq. The results highlighted that venom production was under a sophisticated regulation. Our findings provide new insights into snake neurotoxin research, meanwhile will facilitate antivenom development, toxin-driven drug discovery and the quality control of JinQianBaiHuaShe. Post ancient duplication mutations shaped modern neurotoxins in the many-banded krait. [Display omitted] [ABSTRACT FROM AUTHOR]

Bitis arietans is a medically important snake found in Sub-Saharan Africa. The envenomation is characterized by local and systemic effects, and the lack of antivenoms aggravates the treatment. This study aimed to identify venom toxins and develop antitoxins. The F2 fraction obtained from Bitis arietans venom (BaV) demonstrated the presence of several proteins in its composition, including metalloproteases. Titration assays carried out together with the immunization of mice demonstrated the development of anti-F2 fraction antibodies by the animals. The determination of the affinity of antibodies against different Bitis venoms was evaluated, revealing that only BaV had peptides recognized by anti-F2 fraction antibodies. In vivo analyses demonstrated the hemorrhagic capacity of the venom and the effectiveness of the antibodies in inhibiting up to 80% of the hemorrhage and 0% of the lethality caused by BaV. Together, the data indicate: (1) the prevalence of proteins that influence hemostasis and envenomation; (2) the effectiveness of antibodies in inhibiting specific activities of BaV; and (3) isolation and characterization of toxins can become crucial steps in the development of new alternative treatments. Thus, the results obtained help in understanding the envenoming mechanism and may be useful for the study of new complementary therapies. [ABSTRACT FROM AUTHOR]

Five peptides were isolated from the venom of the Mexican scorpion Centruroides bonito by chromatographic procedures (molecular weight sieving, ion exchange columns, and HPLC) and were denoted Cbo1 to Cbo5. The first four peptides contain 66 amino acid residues and the last one contains 65 amino acids, stabilized by four disulfide bonds, with a molecular weight spanning from about 7.5 to 7.8 kDa. Four of them are toxic to mice, and their function on human Na+ channels expressed in HEK and CHO cells was verified. One of them (Cbo5) did not show any physiological effects. The ones toxic to mice showed that they are modifiers of the gating mechanism of the channels and belong to the beta type scorpion toxin (β-ScTx), affecting mainly the Nav1.6 channels. A phylogenetic tree analysis of their sequences confirmed the high degree of amino acid similarities with other known bona fide β-ScTx. The envenomation caused by this venom in mice is treated by using commercially horse antivenom available in Mexico. The potential neutralization of the toxic components was evaluated by means of surface plasmon resonance using four antibody fragments (10FG2, HV, LR, and 11F) which have been developed by our group. These antitoxins are antibody fragments of single-chain antibody type, expressed in E. coli and capable of recognizing Cbo1 to Cbo4 toxins to various degrees.

Snakebite accident treatment requires the administration of antivenoms that provide efficacy and effectiveness against several snake venoms of the same genus or family. The low number of immunogenic components in venom mixtures that allow the production of antivenoms consequently gives them partial neutralization and a suboptimal pharmacological response. This study evaluates the immunorecognition and neutralizing efficacy of the polyvalent anticoral antivenom from the Instituto Nacional de Salud (INS) of Colombia against the heterologous endemic venoms of Micrurus medemi, and M. sangilensis, and M. helleri by assessing immunoreactivity through affinity chromatography, ELISA, Western blot, and neutralization capability. Immunorecognition towards the venoms of M. medemi and M. sangilensis showed values of 62% and 68% of the protein composition according to the immunoaffinity matrix, respectively. The analysis by Western blot depicted the highest recognition patterns for M. medemi, followed by M. sangilensis, and finally by M. helleri. These findings suggest that the venom compositions are closely related and exhibit similar recognition by the antivenom. According to enzyme immunoassays, M. helleri requires a higher amount of antivenom to achieve recognition than the others. Besides reinforcing the evaluation of INS antivenom capability, this work recommends the use of M. helleri in the production of Colombian antisera.

Sebastián Estrada-Gómez,1– 3,* Leidy Johana Vargas-Muñoz,2,4,* Luis Felipe Higuita-Gutiérrez4,5,* 1Grupo de Toxinologia y Alternativas Terapeuticas Alimentarias, Universidad de Antioquia UdeA, Medellin, Antioquia, Colombia; 2Tech Life Saving (TLS), Medellin, Antioquia, Colombia; 3Centro de Investigación en Recursos Naturales y Sustentabilidad, Universidad Bernardo O’Higgins, Santiago de Chile, Chile; 4Facultad de Medicina, Universidad Cooperativa de Colombia, Medellin, Antioquia, Colombia; 5Escuela de Microbiología, Universidad de Antioquia UdeA, Medellin, Antioquia, Colombia*These authors contributed equally to this workCorrespondence: Sebastián Estrada-Gómez, Email sebastian.estrada@udea.edu.co; direcciontls@udea.edu.coIntroduction: Snakebite envenomation is a public health event of mandatory reporting in Colombia. It is considered a medical emergency in which the government must guarantee antivenom availability. We describe snakebite epidemiological figures in Colombia between 2008 and 2020 and correlate them with antivenom manufacturing figures to determine rate coverage and the need for antivenom.Methods: We performed an ecological study based on secondary official figures from the National Health Institute, the National Institute for Surveillance of Medicines and Foods, the National Administrative Department of Statistics and the Ministry of Health and Social Protection. Absolute and relative frequencies were calculated with 95% confidence intervals, position measurements, dispersion and central tendency.Results: Through our research, we revealed that in the last 13 years (2008– 2020), there were an average of 4467 annual snakebite envenomation cases affecting all the departments in Colombia. Antioquia reported the highest number of snakebites with 647 (95% CI 588– 706) cases per year. The population incidence per 100,000 inhabitants was 9.5; the highest rates were found in Vaupés at 116.1 and Guaviare at 79.24. During the last seven years (2014– 2020) Colombia produced an average of 21,104 antivenom vials per year, while the annual demand for antivenom is estimated at 54,440 units needed to guarantee access.Discussion: Colombia does not produce sufficient vials to cover their needs, and this is why only 74.4% of accidents (out of the 92% not classified as dry bites) were treated, and even 9.7% of the severe accidents did not receive the specific treatment (8% of the victims were classified as dry bites). Figures support the regular antivenom shortages declared by the Ministry of Health and Social Protection in the last 13 years (11 health emergency declarations). New efforts are needed to: 1) boost the production of GMP-based high-quality antivenom, that covers the national needs and is made availability, 2) a better estimation method to calculate the need for antivenom in Colombia, and 3) implementation of production-distribution chains guaranteeing access in remote communities.Graphical Abstract: Keywords: snakebite, Colombia, antivenoms, manufacture, access, availability

Africa remains one of the regions with the highest incident and burden of snakebite. The goal of the World Health Organization to halve the global burden of snakebite by 2030 can only be achieved if sub-optimal access to antivenoms in the most affected regions is addressed. We identified upstream, midstream, and downstream factors along the antivenom value chain that prevent access to antivenoms in the African region. We identified windows of opportunities that could be utilized to ensure availability, accessibility, and affordability for snakebite endemic populations in Africa. These include implementation of multicomponent strategies such as intensified advocacy, community engagement, healthcare worker trainings, and leveraging the institutional and governance structure provided by African governments to address the challenges identified.

Several scientific studies to evaluate the process of digestion and fractionation of immunoglobulins have been carried out in order to improve the production of hyperimmune sera. Today, quality, safety, and production efficiency, along with the development of optimized, robust, and cost-effective processes are priorities. Thus, this work analyzed previous studies of enzymatic digestion of heterologous immunoglobulin G, as well as studies of protein fractionation with caprylic acid, to verify the experimental conditions and their impacts on production processes. The establishment of possible variables; such as concentration, pH, time, and temperature; may allow optimization of the production of hyperimmune sera. Most of the digestive processes evaluated took place at 37° C, pH 3.2, with times longer than 90 minutes, and pepsin inactivation between pH 7.0 and 7.2, while fractionation with caprylic acid used a concentration of 5%, 37° C, and pH 5.0–5.8, for 60 minutes. This work aimed to establish, the ideal conditions to be applied in the production of hyperimmune sera. [ABSTRACT FROM AUTHOR]

Cases of snakebites especially with an elapidae are considered as a medical emergency. However, in some cases of elapidae envenomation, bite signs might be unpredictable.Case: Dorsal surface of the second finger of a 39-year-old man was bitten by N. Naja Oxiana less than half hour before his admission. On arrival, patient had clear bilateral ptosis, mydriasis, reduced light reflex of pupils and sialorrhea. Other muscles power had no problem. The patient was agitated due to suffocation secondary to respiratory muscle paralysis, during half hours of hospitalization. He was intubated and mechanically ventilated. He was treated by antivenom, 10 vials as attack dose, 5 vials as repeated dose that was repeated three times and 2 vials every 8 hours as maintenance dose. He received antibiotic for local superinfection. Although, he did not receive any acetylcholinesterase inhibitors, he was extubated 48 hours later. The patient was discharged on the 7th day in good general condition with oral antibiotic prescription and no complication except local cellulitis. In conclusion, for efficient treatment of patients bitten with elapidae, we need to find the best course of treatment using the adequate antivenom as fast as possible.

The medical humanitarian organization Médecins Sans Frontières (MSF) provides medical care in more than 70 countries and admits more than 7000 cases of snakebite in its facilities each year.We describe our activities against snakebite in three African countries: Central African Republic, South Sudan and Ethiopia, in which different models of care have been developed. A standard protocol using two different antivenoms depending on the patient's syndrome has been introduced, and a simple blood coagulation test is performed to detect venom-induced coagulopathy. Other services, including surgery for necrotizing wounds, are offered in the facilities where MSF admits a large number of snakebite patients. All services, including provision of antivenom, are offered free-of-charge in MSF-supported facilities. Community-based activities focusing on preventive measures and prompt transport to hospital have been developed in a few MSF projects.The provision of quality care and treatment, including effective antivenoms, without out-of-pocket payments by the patients, probably explains why MSF has admitted an increasing number of snakebite victims over the last years. This model requires significant resources and monitoring, including regular training of healthcare workers on treatment protocols and a considerable budget for antivenom procurement.

The most enigmatic group of rattlesnakes is the long-tailed rattlesnake group, consisting of three species: Crotalus ericsmithi , Crotalus lannomi and Crotalus stejnegeri. These species have been the least studied rattlesnakes in all aspects, and no study on the characterization of their venoms has been carried out to date. Our main objective was to investigate the proteomic composition, as well as some of the biochemical and toxic activities of these venoms, and their neutralization by commercial antivenom. The venom proteome of C. ericsmithi mainly contains metalloproteinases (SVMP; 49.3%), phospholipases A 2 (PLA 2 ; 26.2%), disintegrins (Dis; 12.6%), and snake venom serine proteases (SVSP; 6.8%), while C. lannomi venom mainly consists of SVMP (47.1%), PLA 2 (19.3%), Dis (18.9%), SVSP (6%) and l -amino acid oxidase (LAAO; 2.6%). For these venoms high lethality was recorded in mice, the most potent being that of C. lannomi (LD 50 of 0.99 μg/g body weight), followed by C. ericsmithi (1.30 μg/g) and finally C. stejnegeri (1.79 μg/g). The antivenoms Antivipmyn® from SILANES and Fabotherapic polyvalent antiviperin® from BIRMEX neutralized the lethal activity of the three venoms. Although this group of snakes is phylogenetically related to the C. viridis group, no neurotoxic components (crotoxin or crotoxin-like proteins) common in rattlesnakes were found in their venoms. This study expands current knowledge on the venoms of understudied snake species of the Mexican herpetofauna. [Display omitted] • First characterization of venoms of long-tailed rattlesnakes is presented. • Crotalus ericsmithi , C. stejnegeri , and C. lannomi venom proteomic profiles have similar protein families. • Metalloproteinases dominte the venoms, and contribute to toxic activities. • The three venoms lack crotoxin heterodimer. • The three venoms have high lethal potencies in mice, which is neutralized by two Mexican antivenoms. [ABSTRACT FROM AUTHOR]

Scorpionism is Brazil's most prevalent envenomation. Treatment typically involves the use of heterologous antivenoms derived from the immunization of horses with crude T. serrulatus venom (TsV). Due to the high toxicity of this immunogen, as well as the particular challenges associated with the use of venoms as antigens, there is interest in exploring new alternatives for reducing their use in antivenom production. In this study, ten linear B-cell epitopes from hyaluronidase and voltage-gated sodium channel toxins, previously identified using the SPOT-synthesis method, were selected to construct a recombinant chimeric MultiEpitopic Protein from T. serrulatus scorpion venom (TsMEP). We demonstrated that TsMEP is non-toxic, and antibodies elicited in rabbits against this antigen exhibited reactivity in ELISA with Brazilian T. serrulatus, T. bahiensis, T. obscurus, and T. stigmurus venoms, as well as with Peruvian Hadruroides lunatus and North African Androctonus australis hector scorpion venoms. In vivo and in vitro neutralization assays revealed that rabbit anti-TsMEP antibodies partially neutralize the hyaluronidase activity of T. serrulatus venom and its lethality. Data presented here suggests that this multiepitopic protein could be a promising candidate in experimental immunization approaches for antivenom production for clinical use against Tityus spp. venoms., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Carlos Delfin Chavez Olortegui has patent TsMEPto produce Tityus serrulatus antivenom (BR 10 2023 027791 8). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Scorpion stings are a public health event in Colombia lacking official epidemiological data, and are considered a medical emergency. Despite the two local producers of antivenoms, neither of them is currently manufacturing scorpion antivenoms. We present the characterization of a lab-scale process to produce the first specific scorpion antivenom for Colombia, formulated to cover scorpion stings produced by Tityus pachyurus, Tityus asthenes, Tityus fuhrmanii, Centruroides spp. To do so, rabbits were immunized by subcutaneous injection with each venom using an immunization program of 3 months. After each rabbit reached the required IgG concentration, rabbits were bled, and plasma was separated by decantation under refrigeration. Immunoglobulins were purified from each hyperimmune plasma using a methodology including precipitation with ammonium sulfate, thermocoagulation, and purification through an ultrafiltration process using a ready-to-use and reusable laboratory crossflow tangential cassette with a polyethersulfone membrane. Each hyperimmune plasma was processed by being separated and freeze-dried at the end of the process. Rabbits were able to produce specific IgG antibodies recognizing the respective immunization venom; even an in vitro interspecies cross-recognition was detected. The separation and purification processes allowed us to obtain IgG products without considerable contaminants (except for albumin). The process was characterized, and critical stages were identified. [ABSTRACT FROM AUTHOR]

Snakebite and its envenomation are a significant health and economic burden worldwide. Animal (horse/sheep)-based immunoglobulins derived from hyperimmune animal serum or plasma is the current treatment modality for snake envenomation. Chicken egg yolk (IgY) antibodies in the recent past have become one of the promising tools for research as an alternative to these mammalian antibodies. IgY have been a reason of debate from past three decades for its applications in snakebite therapy. The ease of producing pure, specific, and high affinity antivenoms have shown that IgY antivenoms can be used for treating snake bites. [ABSTRACT FROM AUTHOR]

Objectives. To assess the productivity and visibility in research, clinical studies, treatment, use and production of antivenoms against poisonous snakes, scorpions and spiders. Methods. Bibliometric analysis of research and other activities. Articles on venoms and antivenoms published between 2000 and 2020 were retrieved from the Scopus database. The records were analyzed by bibliometric indicators including number of documents per year, journals, authors, and citation frequency. VOSviewer® v.1.6.13 was used to construct bibliometric networks for country co-authorships and co-occurrence of terms. Results. Australia, Brazil, Costa Rica and India were among the six top countries with most documents and were selected for more detailed analysis. Costa Rica was the country with the largest percentage of its publications dedicated to antivenom production and venomics. Only a few papers dealt with the issues of quality, safety, and efficacy of antivenoms or the role of the national regulatory authorities. The use of VOSviewer® allowed visualization through joint publications of networking between countries. Visualization by co-occurrence of terms showed differences in the research carried out. Conclusions. Working in a collaborative and coordinated manner these four countries could have a major impact on envenoming globally. Attention should be given not only to antivenom production but also to strengthening regulatory oversight of antivenom products.

Bitis arietans is a medically important snake found in Sub-Saharan Africa. The envenomation is characterized by local and systemic effects, and the lack of antivenoms aggravates the treatment. This study aimed to identify venom toxins and develop antitoxins. The F2 fraction obtained from Bitis arietans venom (BaV) demonstrated the presence of several proteins in its composition, including metalloproteases. Titration assays carried out together with the immunization of mice demonstrated the development of anti-F2 fraction antibodies by the animals. The determination of the affinity of antibodies against different Bitis venoms was evaluated, revealing that only BaV had peptides recognized by anti-F2 fraction antibodies. In vivo analyses demonstrated the hemorrhagic capacity of the venom and the effectiveness of the antibodies in inhibiting up to 80% of the hemorrhage and 0% of the lethality caused by BaV. Together, the data indicate: (1) the prevalence of proteins that influence hemostasis and envenomation; (2) the effectiveness of antibodies in inhibiting specific activities of BaV; and (3) isolation and characterization of toxins can become crucial steps in the development of new alternative treatments. Thus, the results obtained help in understanding the envenoming mechanism and may be useful for the study of new complementary therapies.

We conducted a retrospective review of Vipera spp. snakebite cases registered by the PCC of Bordeaux, France, between January 1, 2018, and December 31, 2020, evaluating the agreement between VipGrade® assessments, toxicologists' assessments, and current guidelines. 133 patients with Vipera aspis snakebites were included. There was 100% agreement in severity grading by PCC guidelines and VipGrade®. However, grading by toxicologists and VipGrade® diverged in 19 cases (85% agreement; κ = 0.80; 95% CI: 0.71 to 0.87). The VipGrade® tool's grading reflects current PCC guidelines, which are authoritative in France, and may allow for a more rapid and standardized determination of management and follow-up of viper-bitten patients. It should be noted, however, that the more complex and dynamic aspects of management are not included in VipGrade®. Its purpose is to supplement, not replace, the advice of the PCC's clinical toxicologists, and this advice should be sought whenever a viper bite is encountered in clinical practice. [ABSTRACT FROM AUTHOR]

Neutralization of lethality in mice model at the preclinical level has been established by the World Health Organization as the gold standard for the evaluation of antivenom efficacy. The assessment of the neutralization profiles of antivenoms helps to discern the efficacy or otherwise of these antivenoms at neutralizing the toxic effects induced by medically significant snake venoms. However, for many antivenoms, information on their preclinical efficacy remains limited. Therefore, to strengthen global efforts at reducing the impact of snakebite envenoming, the provision of information on the preclinical efficacy of antivenoms, especially in parts of the world where antivenom availability and accessibility is problematic, including sub-Saharan Africa is crucial. This study presents the lethal and toxic activities of N. ashei venom and the neutralizing capacity of two commonly used commercial antivenoms in Kenya; VINS™ and Inoserp™. Median lethal dose (LD50), minimum necrotizing dose (MND) and minimum edema-forming dose (MED) of N. ashei venom as well as the neutralization of these effects were evaluated in mice. The LD50 of N. ashei venom was found to be 4.67 (3.34–6.54) mg/kg while MND and MED were 11.00 μg and 0.80 μg respectively. Both VINS™ and Inoserp™ antivenoms demonstrated capacity to neutralize the lethal and toxic effects induced by Naja ashei venom albeit at varying efficacies. Our results thus confirm the toxic effects of N. ashei venom as previously observed with other Naja sp. venoms and also underscore the relevance of para-specific neutralizing capacity of antivenoms in the design of antivenoms.

This study aimed to determine the efficacy of Inoserp, Vins bioproducts, and South African Institute of Medical Research (SAIMR) polyvalent antivenoms in neutralizing Naja ashei venom-induced lethality in mice. The neutralization efficacy of the antivenoms were expressed as effective dose, median effective ratio, potency, normalized potency, volume, and the number of vials of antivenom required to neutralize 100 mg of Naja ashei venom (NAV).

Cases of snakebites especially with an elapidae are considered as a medical emergency. However, in some cases of elapidae envenomation, bite signs might be unpredictable. Case: Dorsal surface of the second finger of a 39-year-old man was bitten by N. Naja Oxiana less than half hour before his admission. On arrival, patient had clear bilateral ptosis, mydriasis, reduced light reflex of pupils and sialorrhea. Other muscles power had no problem. The patient was agitated due to suffocation secondary to respiratory muscle paralysis, during half hours of hospitalization. He was intubated and mechanically ventilated. He was treated by antivenom, 10 vials as attack dose, 5 vials as repeated dose that was repeated three times and 2 vials every 8 hours as maintenance dose. He received antibiotic for local superinfection. Although, he did not receive any acetylcholinesterase inhibitors, he was extubated 48 hours later. The patient was discharged on the 7th day in good general condition with oral antibiotic prescription and no complication except local cellulitis. In conclusion, for efficient treatment of patients bitten with elapidae, we need to find the best course of treatment using the adequate antivenom as fast as possible. [ABSTRACT FROM AUTHOR]

Instituto Butantan (São Paulo, Brazil) and Instituto Clodomiro Picado (San José, Costa Rica) are public institutions devoted to scientific and technological research, production of antivenoms and other immunobiologicals, and a variety of public health interventions aimed at confronting the problem of snakebite envenoming in their countries and elsewhere. In the context of the 120th anniversary of Instituto Butantan, this work describes the historical developments in the relationship between these institutions, which has evolved into a solid cooperation platform in science, technology, and public health. The relationship between Instituto Butantan and Costa Rica started early in the 20th century, with the provision of Brazilian antivenoms to Costa Rica through the coordination of Instituto Butantan and the health system of Costa Rica, with the leadership of Clodomiro Picado Twight. After the decade of 1980, a prolific collaborative network has been established between Instituto Butantan and Instituto Clodomiro Picado (founded in 1970) in the areas of scientific and technological research in pharmacology, biochemistry, experimental pathology, immunology, and public health, as well as in antivenom development, production, preclinical evaluation, and quality control. In addition, both institutions have played a key role in the integration of regional efforts in Latin America to create a network of public institutions devoted to antivenom production and quality control, in close coordination with the Pan American Health Organization (PAHO). This long-standing partnership is an example of a highly productive south-south cooperation under a frame of solidarity and public well-being. [Display omitted] • Instituto Butantan and Instituto Clodomiro Picado have had a long collaboration. • Instituto Butantan provided antivenoms to Costa Rica in the 20th century. • A collaborative research agenda had developed between these institutions. • Both institutions have played a key role in regional public health efforts. • This collaboration has been based on a frame of solidarity and mutual benefit. [ABSTRACT FROM AUTHOR]

The Andaman and Nicobar Islands are an abode to a diversity of flora and fauna, including the many endemic species of snakes, such as the elusive Andaman cobra (Naja sagittifera). However, the ecology and evolution of venomous snakes inhabiting these islands have remained entirely uninvestigated. This study aims to bridge this knowledge gap by investigating the evolutionary history of N. sagittifera and its venom proteomic, biochemical and toxicity profile. Phylogenetic reconstructions confirmed the close relationship between N. sagittifera and the Southeast Asian monocellate cobra (N. kaouthia). Overlooking this evolutionary history, a polyvalent antivenom manufactured using the venom of the spectacled cobra (N. naja) from mainland India is used for treating N. sagittifera envenomations. Comparative evaluation of venoms of these congeners revealed significant differences in their composition, functions and potencies. Given the close phylogenetic relatedness between N. sagittifera and N. kaouthia , we further assessed the cross-neutralising efficacy of Thai monovalent N. kaouthia antivenom against N. sagittifera venoms. Our findings revealed the inadequate preclinical performance of the Indian polyvalent and Thai monovalent antivenoms in neutralising N. sagittifera venoms. Moreover, the poor efficacy of the polyvalent antivenom against N. naja venom from southern India further revealed the critical need to manufacture region-specific Indian antivenoms. [ABSTRACT FROM AUTHOR]

ABSTRACT Snake envenoming is a neglected tropical disease that affects more than 2.7 million people worldwide. The treatment is based on the administration of antivenom composed of heterologous immunoglobulins, species-specific therapy involving the possibility of adverse reactions due to activation of the immune system. Considering the scarcity of prospective studies evaluating the safety of snake antivenoms, this study aimed to describe and characterize adverse events after antivenom infusion in an observational, prospective, single-centre investigation conducted in a referral centre in Brazil. A total of 47 victims of snake envenoming were included in the study, who were mostly men (75%), with ages ranging from 2 to 83 years. Twenty-two participants (47%) presented manifestations compatible with infusion-related reactions (IRRs) during or up to two hours after F(ab’)2 heterologous immunoglobulin infusion. The most common clinical manifestation related to the infusion was a diffuse cutaneous rash (82%), followed by respiratory manifestations (46%) and facial swelling (23%). In four cases (9%), IRR were considered serious adverse events (SAE), characterized by haemodynamic instability, airway obstruction or hypoxia. Only one patient developed symptoms compatible with serum sickness. Although almost half of the patients treated with antivenom sera experienced IRRs, the SAE rate was 9%; in all cases, the adverse reaction was reversible by using supportive treatment, and there were no deaths. The results have shown that there is much to improve in the antivenom production process to obtain a more purified and specific product. Even so, a timely antivenom serum administration managed by well-trained health teams is safe and prevents complications after snake-related accidents.

Access to safe, effective, quality-assured antivenom products that are tailored to endemic venomous snake species is a crucial component of recent coordinated efforts to reduce the global burden of snakebite envenoming. Multiple access barriers may affect the journey of antivenoms from manufacturers to the bedsides of patients. Our review describes the antivenom ecosystem at different levels and identifies solutions to overcome these challenges.At the global level, there is insufficient manufacturing output to meet clinical needs, notably for antivenoms intended for use in regions with a scarcity of producers. At national level, variable funding and deficient regulation of certain antivenom markets can lead to the procurement of substandard antivenom. This is particularly true when producers fail to seek registration of their products in the countries where they should be used, or where weak assessment frameworks allow registration without local clinical evaluation. Out-of-pocket expenses by snakebite victims are often the main source of financing antivenoms, which results in the underuse or under-dosing of antivenoms, and a preference for low-cost products regardless of efficacy. In resource-constrained rural areas, where the majority of victims are bitten, supply of antivenom in peripheral health facilities is often unreliable. Misconceptions about treatment of snakebite envenoming are common, further reducing demand for antivenom and exacerbating delays in reaching facilities equipped for antivenom use.Multifaceted interventions are needed to improve antivenom access in resource-limited settings. Particular attention should be paid to the comprehensive list of actions proposed within the WHO Strategy for Prevention and Control of Snakebite Envenoming.

The Andaman and Nicobar Islands are an abode to a diversity of flora and fauna, including the many endemic species of snakes, such as the elusive Andaman cobra (Naja sagittifera). However, the ecology and evolution of venomous snakes inhabiting these islands have remained entirely uninvestigated. This study aims to bridge this knowledge gap by investigating the evolutionary history of N. sagittifera and its venom proteomic, biochemical and toxicity profile. Phylogenetic reconstructions confirmed the close relationship between N. sagittifera and the Southeast Asian monocellate cobra (N. kaouthia). Overlooking this evolutionary history, a polyvalent antivenom manufactured using the venom of the spectacled cobra (N. naja) from mainland India is used for treating N. sagittifera envenomations. Comparative evaluation of venoms of these congeners revealed significant differences in their composition, functions and potencies. Given the close phylogenetic relatedness between N. sagittifera and N. kaouthia, we further assessed the cross-neutralising efficacy of Thai monovalent N. kaouthia antivenom against N. sagittifera venoms. Our findings revealed the inadequate preclinical performance of the Indian polyvalent and Thai monovalent antivenoms in neutralising N. sagittifera venoms. Moreover, the poor efficacy of the polyvalent antivenom against N. naja venom from southern India further revealed the critical need to manufacture region-specific Indian antivenoms.

Snakebite envenoming is a major cause of morbidity and mortality in rural communities throughout the tropics. Generally, the main clinical features of snakebites are local swelling, tissue necrosis, shock, spontaneous systemic hemorrhage, incoagulable blood, paralysis, rhabdomyolysis, and acute kidney injury. These clinical manifestations result from complex biochemical venom constituents comprising of cytotoxins, hemotoxins, neurotoxins, myotoxins, and other substances. Timely diagnosis of envenoming and identification of the responsible snake species is clinically challenging in many parts of the world and necessitates prompt and thorough clinical assessment, which could be supported by the development of reliable, affordable, widely-accessible, point-of-care tests. Conventional antivenoms based on polyclonal antibodies derived from animals remain the mainstay of therapy along with supportive medical and surgical care. However, while antivenoms save countless lives, they are associated with adverse reactions, limited potency, and are relatively inefficacious against presynaptic neurotoxicity and in preventing necrosis. Nevertheless, major scientific and technological advances are facilitating the development of new molecular and immunologic diagnostic tests, as well as a new generation of antivenoms comprising human monoclonal antibodies with broader and more potent neutralization capacity and less immunogenicity. Repurposed pharmaceuticals based on small molecule inhibitors (e.g., marimastat and varespladib) used alone and in combination against enzymatic toxins, such as metalloproteases and phospholipase A2s, have shown promise in animal studies. These orally bioavailable molecules could serve as early interventions in the out-of-hospital setting if confirmed to be safe and efficacious in clinical studies. Antivenom access can be improved by the usage of drones and ensuring constant antivenom supply in remote endemic rural areas. Overall, the improvement of clinical management of snakebite envenoming requires sustained, coordinated, and multifaceted efforts involving basic and applied sciences, new technology, product development, effective clinical training, implementation of existing guidelines and therapeutic approaches, supported by improved supply of existing antivenoms.

Snakebite envenoming is a neglected tropical disease that predominantly affects impoverished rural communities in sub-Saharan Africa, Asia, and Latin America. The global efforts to reduce the impact of this disease must consider the local national contexts and, therefore, comparative studies on envenomings in different countries are necessary to identify strengths, weaknesses and needs. This work presents a comparative analysis of snakebite envenomings in Costa Rica, Sri Lanka, and Nigeria. The comparison included the following aspects: (a) burden of envenomings, (b) historical background of national efforts to confront envenomings, (c) national health systems, (d) antivenom availability and accessibility including local production, (e) training of physicians and nurses in the diagnosis and management of envenomings, (f) prevention campaigns and community-based work, (g) scientific and technological platforms in these topics, and (h) international cooperation programs. Strengths and weaknesses were identified in the three contexts and several urgent tasks to improve the management of this disease in these countries are highlighted. This comparative analysis could be of benefit for similar studies in other national and regional contexts.

Background: Snake bite remains major public health problems worldwide. The objective of this study was to determine predictors of in-hospital mortality in patients presenting with snake bite in population of Karachi, Pakistan. Materials & Methods: It was cross-sectional study conducted at Department of General Medicine, Postgraduate Medical Center, Karachi, Pakistan from 11th June 2016 to 10th August 2017. 300 patients with snake bite were selected. Age, gender, acute kidney injury, vomiting and in-hospital mortality were variables. Except age, all variables were nominal and were analyzed by frequency and percentage. Cox-proportional-hazard regression model was applied and hazard ratios were calculated along with 95% confidence intervals (CI) to assess the strength of association between predictors i.e. age, gender, AKI and vomiting and outcome (in-hospital mortality). Kaplan-Meier and time to event plot were used to investigate all patients who were on follow-up for 7 days from admission. Log-rank test was used to identify the predictors of in-hospital mortality for significant independent influence on prognosis at alpha .05. Results: The mean age of the sample was 27.7±14.58 years. Out of a sample of 300 patients, 221 (73.7%) were males and 79 (26.3%) females. The frequency (%) of AKI was 102 (66%), vomiting 122 (40.7%) and of in-hospital mortality 31 (10.3%). The probability of survival at day 7 was 81.8%. Vomiting [hazard ratio 6.86 (95% CI: 2.78-16.93), p=

Objectives: We sought to review the management of scorpion stings in tertiary and secondary care emergency departments in Oman and determine physician’s knowledge of management protocols. Methods: We conducted a retrospective study of all scorpion stings cases seen in Sultan Qaboos University Hospital (SQUH) emergency department (ED) from March 2016 to July 2017. Additionally, we conducted a survey of ED physicians regarding their management of scorpion stings in three different EDs including SQUH. Results: The total number of scorpion stings seen at SQUH during the study period was 128. Localized pain was seen in 97.7% (n = 125), swelling in 14.8% (n = 19), and local redness in 7.0% (n = 9) of patients. Around 13.0% (n = 17) of patients were found to have systemic symptoms with tachycardia being the most common. Bedside clotting test was done for 11.7% (n = 15) of patients. The most commonly used treatment was local anesthesia (54.7%, n = 70). No patient received scorpion antivenom. In the 89 surveyed physicians the main management method used was analgesia (88.8%, n = 71) followed by local anesthesia (81.1%, n = 65). Most physicians (80.0%, n = 64) believed that local anesthesia was the most effective management. However, 32.5% (n = 26) ordered a whole blood bedside clotting test, 69.2% (n = 18) of which were junior doctors. Conclusions: Most scorpion sting cases managed in SQUH had local symptoms. Tachycardia was the most common systemic manifestation. Bedside clotting test was not commonly ordered and mainly requested by junior doctors. Local anesthesia infiltration is the recommended management for scorpion sting. Analgesia was the main management followed by local anesthesia.

Scorpion stings are a public health event in Colombia lacking official epidemiological data, and are considered a medical emergency. Despite the two local producers of antivenoms, neither of them is currently manufacturing scorpion antivenoms. We present the characterization of a lab-scale process to produce the first specific scorpion antivenom for Colombia, formulated to cover scorpion stings produced by Tityus pachyurus, Tityus asthenes, Tityus fuhrmanii, Centruroides spp. To do so, rabbits were immunized by subcutaneous injection with each venom using an immunization program of 3 months. After each rabbit reached the required IgG concentration, rabbits were bled, and plasma was separated by decantation under refrigeration. Immunoglobulins were purified from each hyperimmune plasma using a methodology including precipitation with ammonium sulfate, thermocoagulation, and purification through an ultrafiltration process using a ready-to-use and reusable laboratory crossflow tangential cassette with a polyethersulfone membrane. Each hyperimmune plasma was processed by being separated and freeze-dried at the end of the process. Rabbits were able to produce specific IgG antibodies recognizing the respective immunization venom; even an in vitro interspecies cross-recognition was detected. The separation and purification processes allowed us to obtain IgG products without considerable contaminants (except for albumin). The process was characterized, and critical stages were identified.

There is an urgent need to strengthen the implementation of the 3Rs principle (Replacement, Reduction and Refinement) in the use of experimental animals in toxinological research and in the assessment of the neutralizing efficacy of snake antivenoms. This is a challenging task owing to the inherent complexity of snake venoms. The state of the art on this topic is hereby reviewed, with emphasis on the studies in which a correlation has been observed between in vivo toxicity tests and in vitro surrogate assays, particularly in the study of lethal activity of venoms and its neutralization. Correlations have been described with some venoms-antivenoms when using: (a) enzyme immunoassays, (b) hemagglutination, (c) enzyme assays (proteinase, phospholipase A2), (d) in vitro coagulant effect on plasma, (e) cell culture assays for cytotoxicity, (f) functional assays for assessing neurotoxicity in vitro, (g) use of hens’ eggs, and (h) antivenomics. Additionally, the routine introduction of analgesia in these assays and the design of more ‘humane’ protocols for the lethality test are being pursued. It is expected that the next years will witness a growing awareness of the relevance of the 3Rs principles in antivenom testing, and that new in vitro alternatives and more ‘humane’ experimental designs will emerge in this field.

Background When snake breeders are bitten by rare snakes, deciding whether to administer snake antivenom can be challenging. Case Presentation A 50‐year‐old man was bitten on the right finger by Boiruna maculata. The next day, his right upper limb exhibited pronounced local manifestations of envenomation. At the first consultation, a dark purple bleeding spot and a necrotic site were present under the fang marks at the bitten finger and his affected limb showed extensive swelling and redness. Snake antivenom was not administered because it was difficult to identify the snake and obtain the antivenom. We performed the pressure immobilization technique to his limb. The patient’s symptoms peaked in severity on the second day of illness. He was discharged with marked improvement. Conclusions We have experienced a case of snakebite envenomation by Boiruna maculata.

This study aimed to improve antivenom production using gamma radiation and calcium phosphate nanoparticles (CPN) as adjuvant. Toxicological and immunological properties of the Naja haje venom before and after exposure to radiation were estimated. The immune response of immunized rabbits was evaluated. Toxicity of irradiated venom was reduced six times as compared to native venom. Moreover, no change in antigenic reactivity between native and irradiated venoms. Serum titer produced with irradiated venom loaded on CPN showed highest titer and neutralization capacity as compared to other sera. Thus, irradiation and nanoparticles adjuvant could be a new approach for snake antivenom production. [ABSTRACT FROM AUTHOR]

Micrurus venoms contain two main groups of toxic protein components: short-chain α-neurotoxins (SNtx) and phospholipases type A 2 (PLA 2). In North America, generally, the Micrurus venoms have low abundance of SNtx compared to that of PLA 2 s; however, both are highly toxic to mammals, and consequently both can play a major role in the envenomation processes. Concerning the commercial horse-derived antivenoms against Micrurus from the North America region, they contain a relatively large amount of antibodies against PLA 2 s, and a low content of antibodies against short chain α-neurotoxins. This is mainly due to the lower relative abundance of SNtxs, and also to its poor immunogenicity due to their size and nature. Hence, Micrurus antivenoms made in North America usually present low neutralizing capacity towards Micrurus venoms whose lethality depend largely on short chain α-neurotoxins, such as South American Micrurus species. Horses were hyperimmunized with either the venom of M. tener (PLA 2 -predominant) or a recombinant short-chain consensus α-neurotoxin (ScNtx). Then, the combination of the two monospecific horse antibodies (anti- M. tener and anti-ScNtx) was used to test their efficacy against eleven Micrurus venoms. The blend of anti- M. tener and anti-ScNtx antibodies had a better capacity to neutralize the lethality of diverse species from North, Central and South American Micrurus venoms. The antibodies combination neutralized both the ScNtx and ten out of eleven Micrurus venom tested, and particularly, it neutralized the venoms of M. distans and M. laticollaris that were neither neutralized by monospecific anti- M. tener nor anti-ScNtx. These results provide a proof-of-principle for using recombinant immunogens to enrich poor or even non-neutralizing antisera against elapid venoms containing short chain α-neurotoxins to develop antivenoms with higher effectiveness and broader neutralizing capacity. [ABSTRACT FROM AUTHOR]

We characterized the hemorrhagic, coagulant and defibrinogenant activities of Lachesis muta venom and evaluated the capacity of the Brazilian antivenoms in neutralizing these activities. The hemorrhagic activity of L. muta venom was similarly neutralized by Bothrops , Bothrops - Lachesis and Bothrops-Crotalus antivenoms. The coagulant and defibrinogenant activities were better neutralized by the Bothrops-Lachesis antivenom. Bothrops-Crotalus antivenom also neutralized these activities, indicating that it can be an alternative to treat Lachesis envenomations when Bothrops-Lachesis antivenom is unavailable. • Lachesis muta venom from Manaus region, Brazil, showed hemorrhagic, coagulant and defibrinogenant activities. • The Bothrops-Lachesis antivenom showed higher neutralization activity than the other antivenoms tested in this study. • Bothrops-Crotalus antivenom can be used as an alternative for the treatment of Lachesis muta envenomations. [ABSTRACT FROM AUTHOR]

There is an urgent need to strengthen the implementation of the 3Rs principle (Replacement, Reduction and Refinement) in the use of experimental animals in toxinological research and in the assessment of the neutralizing efficacy of snake antivenoms. This is a challenging task owing to the inherent complexity of snake venoms. The state of the art on this topic is hereby reviewed, with emphasis on the studies in which a correlation has been observed between in vivo toxicity tests and in vitro surrogate assays, particularly in the study of lethal activity of venoms and its neutralization. Correlations have been described with some venoms-antivenoms when using: (a) enzyme immunoassays, (b) hemagglutination, (c) enzyme assays (proteinase, phospholipase A2), (d) in vitro coagulant effect on plasma, (e) cell culture assays for cytotoxicity, (f) functional assays for assessing neurotoxicity in vitro , (g) use of hens' eggs, and (h) antivenomics. Additionally, the routine introduction of analgesia in these assays and the design of more 'humane' protocols for the lethality test are being pursued. It is expected that the next years will witness a growing awareness of the relevance of the 3Rs principles in antivenom testing, and that new in vitro alternatives and more 'humane' experimental designs will emerge in this field. [ABSTRACT FROM AUTHOR]

Objectives. To assess the productivity and visibility in research, clinical studies, treatment, use and production of antivenoms against poisonous snakes, scorpions and spiders. Methods. Bibliometric analysis of research and other activities. Articles on venoms and antivenoms published between 2000 and 2020 were retrieved from the Scopus database. The records were analyzed by bibliometric indicators including number of documents per year, journals, authors, and citation frequency. VOSviewer® v.1.6.13 was used to construct bibliometric networks for country co-authorships and co-occurrence of terms. Results. Australia, Brazil, Costa Rica and India were among the six top countries with most documents and were selected for more detailed analysis. Costa Rica was the country with the largest percentage of its publications dedicated to antivenom production and venomics. Only a few papers dealt with the issues of quality, safety, and efficacy of antivenoms or the role of the national regulatory authorities. The use of VOSviewer® allowed visualization through joint publications of networking between countries. Visualization by co-occurrence of terms showed differences in the research carried out. Conclusions. Working in a collaborative and coordinated manner these four countries could have a major impact on envenoming globally. Attention should be given not only to antivenom production but also to strengthening regulatory oversight of antivenom products. [ABSTRACT FROM AUTHOR]

Snake envenoming is a neglected tropical disease that affects more than 2.7 million people worldwide. The treatment is based on the administration of antivenom composed of heterologous immunoglobulins, species-specific therapy involving the possibility of adverse reactions due to activation of the immune system. Considering the scarcity of prospective studies evaluating the safety of snake antivenoms, this study aimed to describe and characterize adverse events after antivenom infusion in an observational, prospective, single-centre investigation conducted in a referral centre in Brazil. A total of 47 victims of snake envenoming were included in the study, who were mostly men (75%), with ages ranging from 2 to 83 years. Twenty-two participants (47%) presented manifestations compatible with infusion-related reactions (IRRs) during or up to two hours after F(ab')2 heterologous immunoglobulin infusion. The most common clinical manifestation related to the infusion was a diffuse cutaneous rash (82%), followed by respiratory manifestations (46%) and facial swelling (23%). In four cases (9%), IRR were considered serious adverse events (SAE), characterized by haemodynamic instability, airway obstruction or hypoxia. Only one patient developed symptoms compatible with serum sickness. Although almost half of the patients treated with antivenom sera experienced IRRs, the SAE rate was 9%; in all cases, the adverse reaction was reversible by using supportive treatment, and there were no deaths. The results have shown that there is much to improve in the antivenom production process to obtain a more purified and specific product. Even so, a timely antivenom serum administration managed by well-trained health teams is safe and prevents complications after snake-related accidents. [ABSTRACT FROM AUTHOR]

Background: Toxinology is a field of toxicology involved in studying toxins from animals, plants and microorganisms. In Colombia, in last thirty years, this area has been mainly studied by Programa de Ofidismo/Escorpionismo of the Universidad de Antioquia, however, some other research groups have been also contributed in our knowledge of venoms, toxin, effects and treatments. Objective: highlights the most important findings in toxinology made by Programa de Ofidismo/Escorpionismo and other research groups in Colombia. Methods: we collected and analyze119 manuscripts dealing with the history of ophidiology and toxinology in Colombia. Results: we describe some useful terms to understand the toxinology and their scopes. In addition, we build a brief history of ophidiology beginning with the period corresponding to the discovery of America, and ending with recent findings. Finally, we perform a great description of several results related to toxin isolation, characterization, antivenoms, clinical trials, new species descriptions, pretoemic and transcriptomic, among other. The nineteens was characterized by the study of snakebites, their clinic manifestations and the use of antivenoms. In addition, the ethnopharmacological studies of medicinal plants used in snakebite treatments began to be explored. The 2000s included the newly ethnopharmacology, toxin isolation, clinical trials, inhibitor studies, scorpion venom characterization and scorpion stings features. Finally, from 2010 until today, proteomic and transcriptomic gave the most important findings. Conclusions: Toxinology works in Colombia have contributed in our knowledge about endemic species, clinical manifestations of snakebites and scorpion stings, however, we invite to Colciencias and other funding agencies to have more resources in order to support more researchers in this field, since, snakebite is a public neglected disease and need more attention from governments and academic people. Finally, we still have ignorance about the venoms of some species and their possible mode of action. In addition, given the complexity of venoms, we ignore the potential use of toxins in current biomedicine. Thus, we must continue performing studies in toxinology.

SnakeMap is a national cloud‐based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community‐based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty‐eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals. [ABSTRACT FROM AUTHOR]

• Aggregate removal in antivenom was achieved with a monolithic stationary phase. • This simple polishing step requires minor sample pretreatment. • It is a negative chromatography step that simplifies its implementation. • Higher quality products could be produced introducing this technique. Antivenom therapy is a critical intervention for treating the more than 5.000.000 envenomation accidents that occur each year around the world. These immunotherapeutic drugs are mostly produced following techniques developed more than fifty years ago with minor changes. Aggregate content has been described as one of the main causes of early adverse effects after intravenous administration of antivenoms. In this work we propose the introduction of a final polishing step to traditional antivenom manufacturing processes aimed at lowering the aggregate content in the final product. The refinement step proposed in this work is based on the selective capture of immunoglobulin aggregates by a cation exchange monolithic stationary phase. We show that this media can effectively remove aggregates in the final product under isotonic ion-strength and mildly acidic conditions following a negative chromatography strategy, thus making it a useful technique for producing higher quality products. [ABSTRACT FROM AUTHOR]

Objective: To explore whether a DNA immunization approach targeting the major haemorrhage molecule of a prothrombin activator-like metalloproteinase from Echis ocellatus (E. ocellatus) venom could be conceived to inspire antibodies with more prominent specificity and equal adequacy to current conventional antivenoms systems. Methods: The isolated DNA EoMP-6 was used as the template for PCR amplification using the EoDC-2-specific forward and reverse primers. A PCR product of approximately 700 bp was obtained and cloned into pSecTag-B expression vector where anti-EoDC-2 antibodies were generated and analysed for their efficacy to neutralise local haemorrhage in vitro and in vivo. Results: Our results suggest that the generated anti-EoDC-2 showed a remarkable efficacy by (a) interfering with the interaction of the recombinant disintegrin “EoDC-2” isolated from the E. ocellatus as well as other viper species to the α2β1-integrins on platelets; (b) complete inhibition of the catalytic site of the metalloproteinase molecules in vitro using an adaptation antibody zymography assay. Furthermore, it has a polyspecific potential and constitutively expressed significant inhibition by cross-reaction and neutralised venom-induced local haemorrhage exerted by different viper species in vivo. The potential characteristic of EoDC-2 against one part (the non-catalytic domain) as opposed to the whole molecule to neutralise its haemorrhagic activity is of crucial importance as it represents a novel approach with greater immunological specificity and fewer hazards, if any, than conventional systems of antivenom production, by exposure large animals that usually being used for the current antivenom production to a less injurious than expression of the whole molecule containing the catalytic metalloprotease domain. Hence, we report for the first time that our preliminary results hold a promising future for antivenom development. Conclusions: Antibodies generated against the E. ocellatus venom prothrombin activator-like metalloprotease and disintegrin-cysteine-rich domains modulated and inhibited the catalytic activity both in vitro and in vivo of venom metalloproteinase disintegrin cysteine rich molecules. Thus, generating of venom specific-toxin antibodies by DNA immunization offer a more rational treatment of snake envenoming than conventional antivenom.